The corrosion of spring can be divided into chemical corrosion and electrochemical corrosion according to the type of reaction.They are the result of changes in the metal atoms on the surface of the spring or the loss of electrons to an ionic state.
If the metal on the surface of the spring simply reacts with the surrounding medium, and the spring causes corrosion, it is called chemical corrosion.For example, the spring is oxidized in the particularly dry atmosphere to form an oxidation film, and the spring is chemically changed with the liquid or impurity in the non-electrolyte liquid, which is a chemical corrosion.
If the spring is in contact with the electrolyte solution, the corrosion caused by the action of the micro battery is called electrochemical corrosion.For example, the spring is in contact with an acid or a salt solution, which is an electrolyte. Due to defects or impurities on the surface of the spring, different potential differences are formed, so that the spring is constantly subjected to electrolytic corrosion.For example, the spring is in the humid atmosphere, because the water vapor in the atmosphere condenses into water film or water bead on the spring surface, and the corrosive gases in the atmosphere (such as sulfur dioxide and hydrogen sulfide in industrial waste gas or salt mist in the ocean atmosphere, etc.) dissolve in water film or water bead to form electrolyte.In addition, impurities or defects of the spring metal can form electrodes with different potential differences, and the spring also produces electrolytic corrosion.These are electrochemical corrosion.
Chemical corrosion of springs is small and slow, while electrochemical corrosion is major and common.But generally speaking, chemical corrosion and electrochemical corrosion exist simultaneously.
The spring is often corroded by the surrounding medium in the process of manufacture, storage and use.As the spring works under the influence of the spring force, the spring force will change and lose its function after being corroded.Therefore, preventing the corrosion of the spring can guarantee the stability of the spring and extend its service life.
The anti-corrosion method of spring generally adopts protective layer, which can be divided into metal protective layer, chemical protective layer, non-metal protective layer and temporary protective layer according to the property of protective layer. The first three methods are emphatically introduced here.
Stainless steel spring and copper wire spring have certain antisepsis ability themselves, do not undertake anticorrosive treatment commonly so.